FORT MYERS, Fla. -- With roster spots up for grabs, camp battles are always an intriguing part of Spring Training, and for the Twins this year, it's all about how the rotation will look come Opening Day.
The Twins figured to have three locks in right-handers Ervin Santana, Jose Berrios and Kyle Gibson, but now that Santana will be out until mid-April or early May after undergoing surgery on his right middle finger, there's even more uncertainty about how the Twins will fill out their pitching staff. Minnesota is also expected to add to its rotation this spring, as it remains in the market for a starting pitcher or two, despite pitchers and catchers reporting on Tuesday.
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The Twins remain interested in several top free-agent starters such as Lance Lynn and Alex Cobb despite losing out on Yu Darvish, as well as back-end options such as Jaime Garcia and Chris Tillman. They're also reportedly interested in trading for Rays right-hander Chris Archer, but it would require a substantial return, including potentially trading players on the Major League roster to acquire Archer, who is under contract with options through 2021.
Adding a starter remains a priority for the Twins, so it's fair to assume the club will fill at least one of its rotation spots with outside help. But there are still two more spots open this spring, unless the club decides to go with a four-man rotation to open the year because of off-days early in the season. Some of that could also depend on how quickly Santana recovers from the injury, as the club wouldn't need a fifth starter until April 9, should it decide to open 2018 with a four-man rotation.
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Left-hander Adalberto Mejia has the leg up on the competition after showing flashes of talent during his rookie season last year, posting a 4.50 ERA in 21 starts. He also made the rotation out of Spring Training in 2017 over Berrios, but Mejia needs to learn to trust his stuff better and attack hitters. He has a good arsenal, as his fastball averaged nearly 93 mph to go along with his slider and changeup, but he lasted an average of only 4 2/3 innings per start.
Right-hander Phil Hughes has to prove he's healthy after undergoing a second rib surgery to alleviate thoracic outlet syndrome. Hughes has dealt with injuries the last three seasons and hasn't topped 60 innings since '15. But he remains under contract through '19, and the Twins aren't ready to give up on him, especially if this second surgery helps him get back on track. It's a huge spring for Hughes to show that he can still be an effective starter, and his velocity will be worth tracking.
The Twins will also get a long look at prospects such as Aaron Slegers, Stephen Gonsalves and Fernando Romero. Slegers isn't as highly regarded as Gonsalves or Romero, who are both Top 100 prospects per MLB Pipeline, but has the advantage because he got a taste of the Majors last year. Gonsalves is considered closer to the Majors than Romero, but Romero has the best stuff of the three starters. All three are likely to open the year at Triple-A Rochester, but each pitcher could factor into the rotation battle. Zack Littell, acquired from the Yankees for Garcia at the 2017 non-waiver Trade Deadline, is also under the radar after going a combined 19-1 with a 2.12 ERA across Class A Advanced and Double-A last year.

Minnesota will also add to its depth by moving both Tyler Duffey and Trevor May back to starting roles, although May isn't expected to be ready to return from Tommy John surgery until early May. Duffey is coming off a down year as a reliever and will need an effective third pitch as a starter to go with his fastball and plus curveball. The 27-year-old righty could go back to the bullpen, but gives the Twins some much-needed rotation depth.